I have "n" documents or files in pdf format, I will upload them in a website but I want to protected or secure them with a Blockchain where they are going to be saved, of course those blocks of the chain should have a hash. When somebody wants to download them, they won´t need to think whether those are fake or real because the can prove them looking at the Blockchain network as Bitcoin network...
1. Who will store (and mine) your blockchain? Or better: what incentives you have in mind for 3rd party to store and mine your blockchain?
2. Is it only you who "uploads" pdfs? Who certifies those pdfs are the "real" ones? Also, most pdfs are worthless, you actually plan to build a platform for certain institutions to store their documents?
3. Let's say somebody wants a pdf. OK. He gets the link, he verifies the checksum. It's legit. But he wanted the pdf with the engine of a rocket and he got the pdf with a novel. The checksum is correct for the pdf, but it's not the expected pdf. What now? How you solve this?
I still don't understand the usefulness and the meaning of this... but from your (vague) explanation it sounds like it may need quite a lot more thinking.